Construction vehicles which manipulate large diameter pipes for construction of pipelines are a specialized type of vehicle, and are generally referred to as "pipelayers". These pipelayers are equipped with specialized tools and frames for supporting and manipulating the large heavy pipe sections. Such tools and frames generally include a pipe supporting boom arm, a counterweight assembly, a draw works or winch assembly, and a pipelayer frame assembly for supporting the boom arm, the counterweight assembly, and the drawworks. Most prior art pipelayers utilize a cable connected between the drawworks and the boom arm, and by running the cable in or out, the boom arm and the pipe are raised and lowered.
More recently, fluid powered linear motors, or cylinders, have been utilized to replace the drawworks and cable for controlling the raising and lowering of the boom arm and pipe. One type of such a device is shown in U.S. Pat. No. 4,042,116, issued to G. M. Bertolino on Aug. 16, 1977. In this patent, maneuvering of the movable boom is controlled by a large hydraulic jack. The jack is connected between one end of the boom and a supplemental support or framework. Another type of structure for maneuvering a boom or jib is shown in U.S. Pat. No. 3,842,983, issued to C. Dolza on Oct. 22, 1974. In this patent, the jib is raised and lowered, and pivoted laterally, by a plurality of hydraulic jacks.
In each of the above noted boom manipulating devices, removal of the boom would normally be necessary to transport the vehicle for a considerable distance. With the boom removed, one end of the cylinder, or cylinders, becomes unsupported, which requires the cylinders to be removed or stored on the machine in some manner. Removal of the fluid cylinders necessitates disconnecting and plugging of several fluid lines. The possibility of fluid loss and contamination of the fluid system is always a concern when fluid lines are disconnected. When the fluid cylinders are removed, they must be stored and shipped separately, thereby requiring additional space and effort. Also, considerable time and effort are required to re-assemble the fluid cylinders to the vehicle.
The present invention is directed to overcoming one or more of the problems as set forth above.